non clipped fish marking

[Tsquared]

In these days of keeping or throwing back salmon based on the clipped adipose fin, I was interested/appalled to talk to a buddy whose dad is involved with salmon enhancement on the Salmon River. He was saying that there are a number of hatcheries who are now marking their hatchery fish prior to release by briefly increasing water temperature at a certain stage in their development. This has the effect of softening a bone in their ear, making a mark on the bone. Different hatcheries do this different numbers of times, thus making a distinctive number of marks on the internal headbone of the fish. They do this to avoid the labour of clipping each individual fish but the bad part for us is those "wild" fish you are releasing could actually be hatchery fish after all. This was the first I had heard of this method of marking fish so I was wondering if anyone else had heard of if.
T2

 

[prm]

The hatchery at Renfrew does that. No fin clip.

 

[tortuga]

There was a bloodied up dfo damsel [] removing and collecting earbones on the docks at Bamfield last Aug.

 

[ratherbefishing]

It is called thermal marking. Changing the thermal regime up and down a number of times and for various lengths of time puts down different thickness layers on the otolith (this is the boney structure in the ear) - it is very effective. I thought lots of places thermally mark all of their fish and clip a %? It is very common with a number of salmon species.

 

[Highliner]

quote:Originally posted by ratherbefishing

It is called thermal marking. Changing the thermal regime up and down a number of times and for various lengths of time puts down different thickness layers on the otolith (this is the boney structure in the ear) - it is very effective. I thought lots of places thermally mark all of their fish and clip a %? It is very common with a number of salmon species.

What I want to know is who the hell figured that out?

 

[Striper Sniper]

So if that is correct, Sportsman have been releasing a lot of hatchery fish in "clipped only" areas...... SS

 

[ratherbefishing]

They also use oxytetracyclene, calcein, and other chemical markers to put marks on otoliths for ID...

Amazing the stuff people figure out...

 

[Barbender]

Typical DFO management. You can keep all the clipped fish you catch....however the fact that they did not clip any fish is never mentioned. The death of the west coast sport fishery is on the horizon. Prices for wild fish have been climbing the last few years due to the pressure from anti-aquaculture activists saying wild is better. Trust me in a few years you wont even be allowed to keep a pink salmon. It is all about the money and there is money to be made on commercially fishing wild salmon. Jimmy and his boys will make sure of it. Mark my words.

 

[Nimo]

The death of the sportfishery Barbender? Don't take up creative writing in your new career.

I recall saying that I wouldn't put farmed salmon in my compost...Let alone eat it[xx(]

 

[Fog Ducker]

Yes sports fishers have definately releasing non clipped hatchery fish in clipped only fisheries. i dont have any numbers but many hatchery fish do not get marked at all, clipped, tagged, thermally or otherwize. The purpose of the thermal marking from what I understand is to provide an easy way of telling different hatchery origins and brood year classes. I think there are only a few hatcheries on the Island that use this method, Robertson Cr and Nitinat for sure do. It can almost provide as much info as a CWT (coded wire tag) that gets implanted into the fishes nose, but it is much more cost effective than the CWT. Also many of these thermal marked fish would also be clipped (again i dont have any numbers). because it is costly to examine the otaliths, they have to be extracted from the head, then split in half, they get lightly burnt to increase the contrast of the markings then examined through a microscope. As you can imagine they do not want to be doing this to a bunch of fish that have no thermal markings (e.g. wild), so they actually do clip many of them. This technique has been goin on for years now, its nothing new. and i think is is to replace CWT's not fin clips, but i could be mistaken. If anyone gets a chance they have a small 'hut' at Robertson Creek Hatchery that explaines it well that is open to the public during parts of the year.

On the other side of things there are wild fish out there that are are clipped. I worked on the Black Creek counting fence for a year and we were clipping and releasing wild fish (coho). So someone could be keeping one of these fish believing its a hatch, when in fact its a wild. This was done to get an idea of CWT tag retention.

Well thats my understanding of this issue
hope this clarifies some questions.

Fog

 

[GLG]

It seems to me that the DFO regulations are not keeping up with the times.
We are led to believe that clipped fish are hatchery fish and non-clipped are wild fish.
At least that’s how I read the regulations and the bulletins. Makes no sense to me that we are only allowed to keep marked (clipped) fish or one wild and one marked fish.
That was for Coho last year where I fish. I’m all for conservation of Salmon stocks but give me a break and cut the bull. If you don’t mark all the hatchery fish (Chinook and Coho) then don’t try and pass this as conservation of wild stocks. What’s next one wild Chinook and one marked for a daily limit? How about only keeping marked fish to preserve the wild stocks. Total BS. We pay for the hatcheries. We volunteer in hatcheries and streams for what purpose? Ask any of your fellow fisherman how you can tell a wild fish from a hatchery fish. Most fishermen are still under the assumption that the unmarked fish you just released was wild and you just did something good. So what’s the solution? Put funding back into the hatcheries so that they can clip all fish or get rid of the release all wild fish for conservation reasons. Rant over but just don’t get me started on the difference between a wild fish and a hatchery fish BS.
GLG

 

[Barbender]

quote:I recall saying that I wouldn't put farmed salmon in my compost...Let alone eat it

I think you missed my point completely. I was pointing out that sport fishing rights are slowly being whittled away every year. With pressure from FN and the Commercial sector we are low on the food chain. Prices for wild fish are at a all time high especially for sockeye and chinook. I won't even mention the price of halibut. Somehow you take that and slam farmed fish. I was merely pointing out the economics that are at play here. As for the farmed salmon dispute I am staying out of it. This site has been hijacked by some questionable people in my mind with regards to that issue.

 

[Fog Ducker]

Below FN Yes, but i think in generall the sport fishery is above the commercial generally, If commercial is open, almost always recreational is, but lots of times no commercial at all and the sporties are fully open. And unless it has changed in the last couple years, from talking to commercial boat skippers (as i used to work on commercial fisheries as an observer) prices are not too hot these last few years. it's not even worth the seiners to catch pink most of the time because custom offloading rates are almost as high as the price they're getting from the packers for the fish. one year they were getting like $0.11 a pound!! theres not a damn thing wrong with them either if everyone wasn't so picky. meanwhile everyones goes to costco to pay $30 for an atlantic fillett.. WTF

Sorry that got a little ranty...

Fog

 

[Degree of Freedom]

How about next offseason...turn off your computer, get off your butt, head down to a hatchery and volunteer your time. I'm sure they won't mind a little free help with the clipping....if they don't want your help, the Streamkeepers will.